code: def pickled_model(trained_model):
      infile = io.BytesIO()
      pickle.dump(trained_model, infile)
      infile.seek(0)
      return infile
  
file_path: m2cgen/tests/conftest.py
imports: import io
  import pickle
  import pytest
  from sklearn.linear_model import LinearRegression
  from tests.utils import get_regression_model_trainer, tmp_dir
label_desc: Use image node_id 5 for calling a global function with example usage: pickled_model(trained_model) and returns: infile